Seven concept cars that should've been built

Auto shows are populated with any number of tantalizing glimpses of future products. Most seem outrageous, while others are merely thinly disguised concept vehicles. Some prove to be little more than a cruel joke. They are so stunning, so obviously great, one wonders why they are never produced. Here are a few lost opportunities, concept cars that should have been built, but never were.

2008 Buick Riviera Concept: If you've seen Buick's 2012 Buick Verano sedan, you might recognize some of the styling that graced this concept car four years ago. Styled in China, where Buick's popularity remains strong, the car captures classic Buick design elements, from a waterfall grille to a boattail rear. Too bad Buick is content to build crossover SUVs and sedans. The brand could use a little glamour from its most glamorous nameplate.

2003 Cadillac Sixteen: Cadillac's advertising slogan, one it lived up to for decades, was "the standard of the world." General Motors sought to re-establish that aura with this lavish 1,000-hp, 16-cylinder sedan. With a 13.6-liter engine under its hood, the Sixteen spans almost 19 feet in length. Its sumptuous interior is a symphony of leather, walnut and aluminum trim. GM never built it. Too bad.

2004 Chevrolet Nomad: Bob Lutz, the development guru who led a product renaissance at GM didn't always get it right. Instead of building this handsome retro-themed compact, Chevy produced the HHR, which resembled the Chrysler PT Cruiser's uglier, fat brother. The Nomad was the better bet. Using the Pontiac Solstice's rear-drive platform, the Nomad used its 170-hp, 2.4-liter, four-cylinder engine. Practicality is rarely this attractive.

2004 Chrysler ME Four Twelve: Even eight years later, it's hard to believe this is a Chrysler, but that was the intent. This mid-engine supercar boasted an 850-hp V-12 using four turbochargers and intercoolers, aluminum block and heads. A seven-speed, dual-clutch transmission routed enough power to allow the speed demon to reach 60 mph in 2.9 seconds. Top speed? North of 240 mph. It was too good to believe Chrysler would ever build it.

2005 Jeep Gladiator: It seems obvious that the executives running DaimlerChrysler were clueless when it came to expanding the Jeep brand. They bypassed this handsome concept, the Gladiator pickup, to build such winners as the slow-selling Compass and Patriot. The Gladiator featured a bed that could be expanded from 5 feet 8 to 8 feet once the tailgate was lowered. It still looks good enough to build. Are you listening, Fiat?

2002 Lincoln Continental Concept: If any car proves that Ford Motor Co. lost its way early in the 21st century, it's this one. Based on a Town Car platform, this rear-drive concept sported a 414-hp, 6.0-liter V-12 engine mated to a six-speed automatic transmission and was sheathed in aluminum and composite body panels and sporting 22-inch wheels.

1998 Plymouth Pronto Spyder: The Pronto Spyder's 225-hp, 4-cylinder engine was mounted behind the seats, but ahead of the rear axle. A five-speed manual transmission and a top speed of 140 mph were enough to light enthusiasts' fires. They didn't get everything right: the body was made of plastic and they didn't build it.